Solar Power at Night: The Liquid Battery

More of the onrushing news that we can indeed transition to a clean, green, renewable, regenerative, sustainable economy.

Being introduced today at the Emtech India Conference is the first liquid battery.

Based on prototypes already built, the operational data suggest these liquid batteries will cost less than a third as much as today's best batteries and could last significantly longer.

From Technology Review article, and video.

The battery is unlike any other. The electrodes are molten metals, and the electrolyte that conducts current between them is a molten salt. This results in an unusually resilient device that can quickly absorb large amounts of electricity. The electrodes can operate at electrical currents "tens of times higher than any [battery] that's ever been measured," says Donald R. Sadow­ay, a materials chemistry professor at MIT and one of the battery's inventors. What's more, the materials are cheap, and the design allows for simple manufacturing.

The first prototype consists of a container surrounded by insulating material. The researchers add molten raw materials: antimony on the bottom, an electrolyte such as sodium sulfide in the middle, and magnesium at the top. Since each material has a different density, they naturally remain in distinct layers, which simplifies manufacturing. The container doubles as a current collector, delivering electrons from a power supply, such as solar panels, or carrying them away to the electrical grid to supply electricity to homes and businesses.

As power flows into the battery, magnesium and antimony metal are generated from magnesium antimonide dissolved in the electrolyte. When the cell discharges, the metals of the two electrodes dissolve to again form magnesium antimonide, which dissolves in the electrolyte, causing the electrolyte to grow larger and the electrodes to shrink.

Sadoway envisions wiring together large cells to form enormous battery packs. One big enough to meet the peak electricity demand in New York City--about 13,000 megawatts--would only fill 60,000 square meters in an underground facility [about the size your average WalMart]. For New York it would require a solar farms of significant size, generating not only enough electricity to meet daytime power needs but enough excess power to charge the batteries for nighttime demand. The first systems will probably store energy produced during periods of low electricity demand for use during peak demand, thus reducing the need for new power plants and transmission lines.

The team hopes that a commercial version of the battery will be available in five years.